Electronic data cables are used in modern communication systems to carry voice and data signals between transmitters and receivers. Electronic data cables typically consist of a number of twisted pairs of insulated copper conductors held together in a common insulating jacket. Each twisted pair of conductors is used to carry a single stream of information. The two conductors are twisted together, at a certain twist rate, so that any external electromagnetic fields tend to influence the two conductors equally, thus a twisted pair is able to reduce crosstalk (XT) caused by electromagnetic coupling from external sources. In a cable, adjacent twisted pairs are typically twisted at different twist rates so that each pair is still exposed to alternating lengths of the two conductors of its neighboring pair. If all twist rates were the same, then one wire of a twisted pair would approximately be the same distance from one of the wires of its neighboring twisted pair, thus allowing the first wire to constantly have the same electromagnetic coupling from a single wire of its neighbor along the wire length. Using different twist rates in one cable reduces crosstalk between twisted pairs.
High bandwidth communication systems may require a number of cables to be routed together in a cable bundle. When two lengths of cable are bundled in parallel, twisted pairs in neighboring cables may have equal twist rates. Thus, crosstalk (unbalanced electromagnetic coupling) between twisted pairs with the same twist rate, each carrying different signals, will be more likely to occur. Electromagnetic coupling of signals between twisted pairs in adjacent cables is referred to as alien crosstalk (AXT).
End portions of the insulated conductors of cables are terminated in corresponding groups slots of a connector block. Termination is effected by insulation displacement contacts seated in the slots. The insulation displacement contacts may be formed from a contact element which is bifurcated so as to define two opposed contact portions separated by a slot into which an insulated conductor may be pressed so that edges of the contact portions engage and displace the insulation and such that the contact portions resiliently engage and make electrical connection with the conductor. Such a contact is described in, for example U.S. Pat. Nos. 4,452,502 and 4,405,187. Two opposed contact portions of the insulation displacement contacts are laid open in the slots. As such, an end portion of an insulated conductor can be electrically connected to an insulation displacement contact by pressing the end portion of the conductor into the slot.
Cable managers have previously been used to locate ends of the cables in fixed positions for presentation to corresponding groups of slots of the connector block. The cable managers have previously been an additional piece of equipment that can be selectively coupled to the connector block for management of the ends of the data cables. Cable managers of this type may add to the cost of an electrical installation that includes a plurality of connector blocks. Further, they may not be convenient to use in locations where space is restricted.
Cable managers of the above-described type may not necessarily retain the insulated conductors of an electronic data cable in substantially fixed positions with respect to the corresponding side of a connector block. As such, the conductors may not necessarily lie flat against the body of the connector block and may be free, to some extent, to move about. This may cause difficulties when connector blocks are stacked on top of one another, for example. In such an arrangement, the separation distance between conductors connected to the connector blocks may be reduced and electromagnetic radiation therebetween may cause alien crosstalk.
It is generally desirable to overcome one or more of the above-described difficulties, or at least provide a useful alternative.